AU627229B2

AU627229B2 - Ink furnishing device for printing machines

Info

Publication number: AU627229B2
Application number: AU42739/89A
Authority: AU
Inventors: Kohmei Kawahara; Yuichi Okamura; Noriyuki Shiba
Original assignee: Tokyo Kikai Seisakusho Co Ltd
Current assignee: Tokyo Kikai Seisakusho Co Ltd
Priority date: 1988-10-14
Filing date: 1989-10-10
Publication date: 1992-08-20
Anticipated expiration: 2009-10-10
Also published as: EP0363825B1; DE68922568T2; DE68922568D1; ATE122288T1; AU4273989A; EP0363825A1

Abstract

This invention is related to an ink furnishing device for printing machines, and some of the rollers which are provided in the intermediate route of the ink furnishing such as an inking roller, fountain roller, and transfer roller is constituted with a minute hollow body dispersing roller. With this roller constitution, the ink transfer action of the roller becomes sure and it is possible to provide a roller that can be used for a long term, and the time period between successive roller exchanges becomes thereby longer and an ink furnishing device with a high machine availability factor can be provided for printing machines.

Description

7969A:rk K 'f I: ii ~or* 627229 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION FOR OFFICE USE Form Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: 0 @0 00 0 *000 0 TO BE COMPLETED BY APPLICANT *0 a *ees 0 0@0e 0 0000 0 0 Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: KABUSHIKIGAISHA TOKYO KIKAI

SEISAKUSHO

26-24, Shiba 5-chome, Minato-ku, TOKYO,

JAPAN

Noriyuki Shiba; Yuichi Okamura and Kohmei Kawahara GRIFFITH HACK CO.

71 YORK STREET SYDNEY NSW 2000

AUSTRALIA

Complete Specification for the invention entitled: INK FURNISHING DEVICE FOR PRINTING

MACHINES

The following statement is a full description of this invention, including the best method of performing it known to me/us:-

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7969A:rk r i 1 ~ll~C6 2 INK FURNISHING DEVICE FOR PRINTING MACHINES BACKGROUND OF THE INVENTION Field of the Invention This invention relates to an ink furnishing device used for rotary printing machines, in which an ink furnishing route is formed by an ink furnishing device such as a fountain roller and an ink form roller which is in contact with a plate.

The present invention is related in particular to a keyless ink furnishing device in which an ink removal member is in contact with the surface of an inking roller in order to remove excess ink and the ink is furnished by the keyless ink furnishing.

The present invention is also related to an ink furnishing device in which the surfaces of a fountain roller and/or transfer roller are constituted with a rough surface.

Description of the Prior Art A keyless ink furnishing device has been used in the field of flexographic printing. It has an ink metering roller, namely an anilox roller on the surface of which minute carved cells of an exquisite and substantially fixed shape are arranged regularly and an ink removal member (for instance, a blade) to remove excess ink which is received in the cells. Both the ink metering roller and the blade work in cooperation, and the ink received in the cells is furnished to the plate during the printing operation.

The anilox roller used for a keyless ink furnishing device has its minute carved cells formed by form rolling or laser beam machining, Sometimes those cells are covered with an adequate material as needed when used for printing.

On the other hand, an ink furnishing device in which at least one of the surfaces of an ink fountain roller W and transfer roller is constituted with a rough surface S:206 OB/438/3.6.92 3 is published, for instance, in Japanese Patent Laid-Open No. 63-222648 'Inking Device' (called hereinafter Prior Art 1) and Japanese Patent Laid-Open No. 63-22649 'Inking Device' (called hereinafter Prior Art both being applied to offset printing machines.

The ink furnishing device in Prior Art 1 transfers ink continuously by making the fountain roller and transfer roller contact each other under pressure with both rollers rotating respectively at different peripheral speeds, and at the same time at least one of the fountain roller and transfer roller has its surface made rough. And, by the rough surface of either one of them the ink is retained in the rough surface and the retained ink provides uniform lubrication at the contact section under pressure of the fountain roller and transfer roller, preventing vibration of both rollers caused by an unstable lubrication at the contact section under pressure. At the same time this prevents the separation of ink and water at the rough surface and makes it possible for dispersal of the water and ink and improves the performance in receiving ink.

The ink furnishing device in Prior Art 2 has a fountain roller made of rubber and it is made to contact directly an inking roller (intermediate roller, drive S 25 roller) to transfer ink between them, and the surface of "the fountain roller is constituted with a rough surface.

oo This ink furnishing device has a construction in which the fountain roller is a rubber roller and it is possible thereby to have a direct contact between the fountain l 30 roller and inking roller, and accordingly a transfer :'"roller which is placed between the fountain roller and inking roller in conventional ink furnishing devices is omitted and the drive means for the transfer roller is 0000eliminated at the same time to make the overall construction simple with reduced cost. The control of the nip between the transfer roller and above mentioned AL1,7 two rollers is normally a problem but is effectively w eliminated, relieving the worker of this work.

S2090B/438/3.6.92 S:208908/438/3.6.92 4 Furthermore, the performance of ink transfer is improved by making the surface of the fountain roller rough.

The continuous contact of surfaces among the inking roller, fountain roller, transfer roller, etc. develops friction and results in their surfaces being worn. The volume of each cell in the surface of the anilox roller (inking roller) in a keyless ink furnishing device becomes smaller by this wear with the result that a smaller amount of the ink can be supplied to the plate and the quality of printing can not be maintained at a constant level.

The rough surface in the prior art of the fountain roller and transfer roller has convex and concave spots formed simply in a certain range (15 20 ym in Prior Art 1 and Prior Art 2) in the roller surface, and the state of roughness is subject to change or can disappear in a short time due to friction between the fountain roller and inking roller or between the fountain roller and transfer roller during a printing operation. Thus the benefits derived from having a rough roller surface, such as prevention of the separation of ink and water, dispersal of ink and water, improved performance in ink receiving, and improved performance in the transfer of ink are diminished or lost in a small amount of time.

25 The frequency of replacing rollers with rough surfaces or reclamation of the rough surface, therefore, rises with e the resultant problem of lowered machine availability.

SUMMARY OF THE PRESENT INVENTION According to one aspect of the present invention 30 there is provided an ink furnishing device for printing machines which comprise a plurality of rollers arranged to form an ink furnishing route interconnecting an ink replenishing means with the surface of a plate, whereby contacting rollers of the furnishing route transfer ink from the replenishing means to the surface of the plate, wherein at least one of the rollers comprises an ink W receiving layer having minute hollow bodies substantially S:20690B/43813.6.92 uniformly dispersed throughout and arranged to be open at the outer peripheral surface of the at least one roller.

Preferred embodiments of the present invention will now be described by way of Example only with reference te the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show embodiments of the present invention in which: Fig. 1 is a perspective view of a roller on which minute hollow bodies are dispersed, Fig. 2 is the view of a partial surface of the roller of Fig. 1, Fig. 3 is the view of a partial surface of the roller of Fig. 2 on which hard material powder is uniformly dispersed, Fig. 4 is a schematic view of an ink furnishing device used for a printing machine in general, Fig. 5 through Fig. 28 are the schematic views of the embodiments in which the inking roller is a roller with minute hollow bodies dispersed on it, Fig. 29, Fig. 30, Fig. 37, Fig. 38, Fig. 39, and Fig. 40 are the schematic views of the embodiments in which the fountain roller is a roller with minute hollow bodies dispersed on it, Fig. 33, Fig. 34, Fig. 41, and Fig. 42 are schematic views of embodiments in which the transfer roller is a roller with minute hollow bodies dispersed on it, and Fig. 36, Fig. 37, Fig. 43, and Fig. 44 are the schematic views of embodiments in which both the fountain roller and transfer roller have minute hollow bodies on them.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Fig. 4 is a representative schematic view of an ink 0furnishing device in general for printing machines to explain its functions. It is constituted with an ink I p LIA furnishing device 3, inking roller 1, ink form roller, E :20690B/438/3.6.92 !i I I- i -6 and plate cylinder P which are successively arranged in this order from the upstream side and all of which are in contact with the neighboring members. An ink removal device 2 which is for removing excessive ink on the circumferential surface of the inking roller in contact with the inking roller and a water supply device D which supplies water to the plate cylinder P to wet it are provided. The ink furnishing device 3 in this drawing consists of a fountain roller 31 and ink reservoir 32.

In Fig. 1, a roller 1 on which minute hollow bodies are dispersed consists of a main body member 16 made from, for instance, a steel stock and an ink receiving layer 11 which has a plurality of mixed materials on the surface of the main body member 16.

In Fig. 2, this ink receiving layer 11 has minute hollow bodies 12 that are substantially uniformly dispersed and those minute hollow bodies 12 which are located on the outer circumferential surface of the roller 1 have a hollow section of the minute hollow body 12 opened.

In Fig. 3, in addition to the minute hollow bodies 13 the layer 11 has powder 13 of a hard material such as hard inorganic material also uniformly dispersed to be mixed among the minute hollow bodies 12 in order to raise 25 the wear resistance of the layer 11.

Each of the minute hollow bodies 12 that are uniformly dispersed on substrate '14 of the ink receiving layer 11 should be open by removing part of its shell.

The minute hollow body 12 is generally called a microballoon, microsphere, hollow balloon, glass balloon, silica balloon, sirus balloon, phenol balloon, vinylidene chloride balloon, alumina balloon, and zirconia balloon, and various hollow powders of various materials are known. One or two example(s) will be mentioned, which 35 include proprietary products such as 'Carbo Sphere' (registered) of VERSAR Manufacturing Inc. of U.S.A. and 'Fillite' (trade name) of Fillite Inc. of U.K. The former product is a carbon balloon, its bulk density 44

S

4) 4 5*

S

5* 5 9 'Ip j S:206908/438/3.6.92 f 1-- -7b~ing 0.15 g/cm 3 and the thickness of the body is in 1 2 Am, and there are four distributions of particle diameters ranging in 50 150 Am (average diameter of Am), 5 100 Am (average of 45 Am), 5 50 Am (average of 30 Am), and 50 150 Am (average of 60 Am). A minute hollow body the surface of which is coated with nickel, iron, copper, gold or other metal is known, and this coating is effective. The last mentioned of the proprietary products is a silica balloon, its bulk density being 0.4 g/cm 3 and the distribution of the particle diameters ranges in 30 300 Im.

In the present invention, minute hollow bodies in which particle diameters are in the range of 5 300 Am are useable. It is easy to provide an inking roller which gives different amounts of ink supply to the plate by changing the ratio of mixture of minute hollow bodies 12 dispersed on the ink receiving layer 11 of the inking roller 1 or/and changing the size of the minute body 12.

The inking roller 1 which is capable of changing the amount of ink taken into the minute hollow bodies dispersed and mixed on the outer circumferential surface face of the inking roller 1 furnishes a proper amount of each coloured ink in multicolour printings where the supply of ink of different physical properties should be balanced in quantity. In the multicolour printing, it is thereby easy to provide an ink furnishing device which can furnish a proper amount of coloured ink for each colour in multicolour printing. This ink furnishing device can be effectively applied to a multicolour rotary press of satellite type, B-B stacking type, B-B laterally arranged type, etc. With the conventional multicolour rotary printing machine, the physical properties of ink change with colour. When all of the colour ink is furnished by using an anilox roller which is provided 35 with cells of an identical capacity, there is an excess or shortage of ink of one colour, causing an imbalance among colours on the print face, and the overall results of the colour printing is not satisfactory in its e 20690B/438/3.6.92 -8 dppeatance. Accordingly, with the above mentioned keyless ink furnishing device for a multicolour rotary printing machine, it is necessary to slightly change the cell capacity in anilox roller depending on the colour, which entails more work in the machining of the cells and the control of wear of the cells. This created the problem of higher cost in running a colour printing machine in comparison with the running of a monocolour rotary printing machine. This problem can be, however, solved by adopting above described of the present invention.

For a hard mate-:ial powder 13 to be used with the minute hollow bodies, a powder of ceramic material, metal, alloy, etc. can be used. The size of the particle in the hard inorganic material powder 13 should be at least 1 100 unm in diameter when it is used in this invention.

Next, the method of manufacture of an inking roller 1 will be explained below. At first, in an inking roller 1 in Fig. 2 minute hollow bodies 12 are uniformly dispersed on the substrate 14 of an ink receiving layer 11. In the inking roller 1 in Fig. 3 minute hollow bodies 12 and hard material powder 13 are uniformly dispersed in the substrate 14 of the ink receiving layer 25 11. This work process is carried out by a method involving mixing or mulling that is suitable for the characteristics of the substrate 14 of the ink receiving layer 11. The substrate 14 of the ink receiving layer 11 thus obtained in which the minute hollow bodies 12 or both the minute hollow bodies 12 and hard material powder 13 are dispersed uniformly covers the surface of the main .:body member 16 to form an ink receiving layer 11. In this process, casting, wrapping, painting, or other suitable methods are used. Next, the ink receiving layer 11 covering the surface of the main body member is ground at the surface of the layer 11,ii, The grinding is LI performed by either a grinding machine or friction between the inking roller 1 and the blade or bar after

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S:20690B/438/3.6.92 d1 -9.

tht inkting roller 1 has been installed on the rotary printing machine. Then with the grinding in the ink receiving layer on which minute hollow bodies 12 are dispersed, the minute hollow bodies 12 which are near the surface of the ink receiving layer 11 have part of the shell removed and expose the inner surface of the hollow body in the surface of the ink receiving layer 11 as shown in Fig. 2. Fig. 3 shows an ink receiving layer 11 on which minute hollow bodies 12 and hard material powder 13 are dispersed and part of the shell layer of a minute hollow body 12 located near the surface of the ink receiving layer 11 which is removed and the inside of the shell exposed and open in the surface of the ink receiving layer and at the same time the hard material powder 13 are exposed at the surface of the ink receiving layer 11.

Next, in Fig. 5 through Fig. 28, various embodiments of the present invention are described and explained in which the inking roller 1 of an offset rotary printing machine related to the present invention is constituted with a roller 10 on which minute hollow bodies are dispersed.

Ink removal device 2, in Fig. 4, comprises a blade 21 which is provided to make contact with the outer 25 circumferential surface of the inking roller 1. The ink furnishing device 3 comprises a fountain roller 31 which provided upstream of the inking roller 1 and rotates with its outer circumferential surface a little apart from that of the inking roller 1 and an ink reservoir 32 which stores the ink with part of the fountain roller 31 immersed in the ink. And, the ink in the ink reservoir 32 receives additional ink during a printing operation to maintain a constant stored ink level as shown by the "arrow mark in the figure.

In Fig. 5 and Fig. 6, ink removal devices are shown :r which are different in form from that in Fig. 4. This device 2 uses, in Fig. 5, a roller 22 in place of the blade 21, which has outer circumferential surface in S w4 06908/438/3.0.92

F_

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i F- lii 10 cbntact with the outer circumferential surface of the inking roller 1 and is either rotated at a speed lower than the peripheral speed of the inking roller 1 or rotated at a speed almost the same as the peripheral speed of the inking roller 1 with a strengthened pressure of contact with the inking roller 1. The ink removal device 2 in Fig. 6 uses a bar 23 in place of the blade 21. The bar 23 is in contact with a side of the outer circumferential surface of the inking roller 1. In Fig.

7 through Fig. 24 the ink removal devices 2 use a blade 21 but it should be understood that they also can use a roller 22 or a bar 23.

In Fig. 7 through Fig. 28, the constitution of the embodiments of the present invention are shown which combines an ink furnishing device 3 to the inking roller 1 with an ink supply route to the inking roller 1 or the plate. In Fig. 7 through Fig. 12, ink reservoir 32 is in the shape of an ink pan or ink fountain to maintain the height of the ink storage always constant. The ink reservoir 32 is a required constituent of the ink furnishing device 3. Fig. 13 through Fig. 18 show ink discharge bodies 33 in the shape of a nozzle, for instance, to discharge a specified volume of ink all the time. The ink discharge body 33 is also a required constituent of the ink furnishing device.. In Fig. 19 through Fig. 28, ink storage bodies 34 or 35 are shown in the shape of an ink pot or ink chamber, to divide at least part of the open section of the ink storage body by part of the circumferential surface of the inking roller 30 1 or fountain roller 31. Those ink storage bodies 34 or 35 are required constituents of the ink furnishing device 3. In Fig. 19 through Fig. 24, an ink storage body 34 which opens part of the open section is used, and in Fig.

through Fig. 28, an ink storage body 35 which closes the open section and at the same time has an ink removal device added to itself is used. In Fig. 25 and Fig. 26, the ink removal device 2 which is installed with the ink S storage body 35 consists of a blade 21 and in Fig. 27 and SOI438I36.92 7 I 1* -11- Fig. 28, the ink removal device 2 which is installed with the ink storage body 35 consists of a bar 23. In Figures 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, and 27, the inking roller 1 directly furnishes ink to the surface of the plate. In Figures 8, 10, 12, 14, 16, 18, 20, 24, 26, and 28, the ink form rollers 4 stand between the inking roller 1 and the plate, and the ink from roller 4 furnishes ink to the plate. In Figures 7, 8, 13, 14, 19, 20, 25, and 26, the ink from the ink reservoir 32, ink discharge body 33 or ink storage body 34 or 35 is directly furnished to the outer circumferential surface of the inking roller 1. Likewise in Fig. 21, 22, 23, and 24, the ink furnishing device 3 is provided with the fountain roller 31 and the ink is furnished to the outer circumferential surface of the inking roller 1 through the fountain roller 31 from the ink reservoir 32, ink discharge body 33, or ink storage body 34 or 35. In Figures 9, 10, 15, 16, 21, 22, 27, and 28, the fountain roller furnishes ink directly to the outer circumferential surface of the inking roller 1. In Figures 11, 12, 17, 18, 23, and 24, a transfer roller 36 is provided between the fountain roller 31 and inking roller 1 and this transfer roller 36 furnishes ink to the outer circumferential surface of the inking roller 1.

25 The fountain roller 31 in this embodiment can be away from or in contact with the outer circumferential surface of the inking roller 1. Further, in this embodiment an film thickness regulating blade 37 is provided near 0 the outer circumferential surface of the fountain roller 30 31 and this blade limits the ink film thickness on the outer circumferential surface of the fountain roller 31 S and ink is furnished to the outer circumferential surface of the inking roller 1 through the transfer roller 36.

:The transfer roller 36 -is, therefore, in contact with both the circumferential surface of the fountain roller 31 and the circumferential surface of the inking roller 1 L1,and the outer circumferential surface of the inking roller 31 is not furnished with excess ink. But on the i

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S:20690B/438/3.6.92

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7 i i i 12 outer pircumferential surface of the inking roller 1 after it has run on the outer circumferential surface of the ink form roller 4, there is ink which was not used because it did not contact images or lines on the plate, that is residual ink is left or transferred. The blade 21 which is a member of the ink removal device 2 is provided to remove the residual ink.

In the embodiments that have been described and explained in the foregoing, the ink is furnished by an ink furnishing device 3 which attaches the ink to the outer circumferential surface of the inking roller 1.

If the ink furnishing device 3 has an ink reservoir 32, at least part of the inking roller 1 or fountain roller 31 is immersed in the ink in the ink reservoir 32.

And, the ink is directly furnished to the circumferential surface of the inking roller 1 or the ink pumped up by the outer circumferential surface of the fountain roller 31 is furnished to the outer circumferential surface of the fountain roller 31 or through a transfer roller 36 from the outer circumferential surface of the fountain roller 31. When the ink furnishing device 3 is provided with an ink discharging body 33, the ink is discharged form it to the outer circumferential surface of the inking roller 1. Alternatively the ink is discharged to 25 the section where the fountain roller 31 and inking roller 1 come close together or the contact section Sbetween them. The ink may also be discharged to the S: "outer circumferential surface of the fountain roller 31 S"and then the ink is furnished directly to the outer circumferential surface of the inking roller 1 from the fountain roller 31 or through the outer circumferential surface of the transfer roller 36 from the fountain roller 31. When the ink furnishing device 3 has an open o b.port and has an ink storage body 34 or 35 in which at least part of the open port is divided by a section of the inking roller or fountain roller 31, the ink is furnished directly to the outer circumferential surface p 'LIU of the inking roller 1 which divides the open port of the 690B/438/3.6.92 I 13 ink storage body 34 or 35 or the ink is furnished to the inking roller 1 from the outer circumferential surface of the fountain roller 31 or through the outer circumferential surface of a transfer roller 36 from the fountain roller 31.

Part of the ink furnished to the inking roller 1 is received in the minute hollow bodies 12 whie-h are open and dispersed and mixed on the outer circumferential surface of the inking roller 1.

Next, the ink removal device 2 which is in contact with the outer circumferential surface of the inking roller 1 removes excess ink that is furnished to the outer circumferential surface of the inking roller 1.

On the outer circumferential surface of the inking roller 1, ink in a proper amount for printing is stored and stays in hollow sections of the minute hollow bodies 12 which act as if they were ink reservoir cells.

On the other hand in Figures 11, 12, 17, 18, 23, and 24, the inking roller 1 has ink furnished on its outer circumferential surface in an amount which is regulated to be proper for printing at the ink furnishing device 3.

Since the furnished ink is received in the open minute hollow bodies on the outer circumferential surface of the inking roller 1, no excess ink exists on the outer S 25 circumferential surface of the inking roller 2, and accordingly removal of excess ink i not needed.

As the inking roller 1 rotates on further, an amount i of the ink on the outer circumferential surface of the o' inking roller 1 which is received in the open minut hollow bodies 12 and suitable for printing is furnished directly or through the outer circumferential surface of the ink form roller 4 to the plate.

On the outer circumferential surface of the inking roller I which has finished furnishing ink directly or through the outer circumferential surface of the ink form roller 4 to the plate from the inking roller 1, the ink L o or not used because it is not required for the images formed j iI ~on the plate, remains on the rollers. In Figures 5, 6, S U) .20690B/438/3.8.92

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14 8, 10, 13, 14, 15, 16, 19, 20, 21, and 22, new ink is furnished on the residual ink and then the excessive ink is removed by the ink removal device blade 21 to make the amount of the ink on the outer circumferential surface of the inking roller 1 adequate, but in Figures 11, 12, 17, 1.8, 23, and 24, if new ink is furnished, sections where the ink is in excess develop on the outer circumferential surface of the inking roller 1 so that the excess ink is removed from the outer circumferential surface of the inking roller 1 by providing the blade 21 which is a member of the ink removal device 2 in contact with the outer circumferential surface of the inking roller 1 that has just finished furnishing ink to the plate.

With the rotation of the inking roller 1 continued, the actions described in the foregoing continue.

On the other hand, the outer circumferential surface of the inking roller 1 wears gradually by the ink removal action of the ink removal device 2 for excessive ink or residual ink staying on the outer circumferential surface of the inking roller 1. The minute hollow bodies 12 are dispersed substantially uniformly in the ink receiving layer 11 provided on the surface of the inking roller and those hollow bodies are exposed to be opened on the outer 25 circumferential surface successively as the wear of the receiving layer 11 proceeds so that the outer circumferential surface of the inking roller 1 develops no significant change until the ink receiving layer 11 wears out. An adequate amount of ink for printing can be, therefore, maintained on the inking roller 1 for an increased length of time.

SFurthermore, when ar inking roller 1 whiCh has on its ink receiving layer 11, the powder of, for instance, a hard inorganic material that is uniformly dispersed, 35 the friction that develops by the ink removal device 2 is I taken up exclusively by the inorganic powder, reducing Sthe wear of the outer circumferential surface of the plLIA 4 inking roller 1. In this case also the state of the :20690B/438/3.6.92 luniuwig statement is a tlu description of this invention, 4.

including the best method of performing it known to me/us:- 7969A:rk oiuter 'circumferential surface of the inking roller 1 develops no significant change until the ink receiving layer 11 wears out. Accordingly, an adequate amount of ink for printing can be furnished for a long period.

Next, in Fig. 29 through Fig. 44, various aspects of the constitution of a second embodiment of the present invention and in which the fountain roller 31 and /or transfer roller 36 have minute holiow bodies 10 on their outer circumferential surface will be explained.

Fig. 29 through Fig. 36 give representative schematic views of the second embodiment. In Figures 29, 31, 33, 35, 37, the ink furnishing device which furnishes ink to the fountain roller 31 is an ink reservoir which stores ink with part of the fountain roller 31 immersed in the ink.

In Figures 30, 32, 34, 36, and 38, the ink furnishing device to furnish ink to the fountain roller 31 is an ink discharge body 33 which discharges ink towards the outer circumferential surface of the fountain roller 31.

In Fig. 29 and Fig. 30, a rotating fountain roller 31, ink furnishing device is provided upstream of the roller 1 and furnishes ink to the outer circumferential surface of the roller 1. Ink form roller 4 which is in contact with the plate on a plate cylinder and rotates to furnish ink to the plate, and inking roller 1 which is placed between the fountain roller 31 and ink form roller 4 and rotates in parallel to them in contact with the outer circumferential surface of the fountain roller 31 and ink form roller 4 are shown, and the fountain roller 31 is the minute hollow body dispersing roller In Fig. 31 through Fig. 36, the rotating fountain roller 31, ink furnishing device is positioned upstream of the roller 1 to furnish ink to its outer circunmferential surface. Ink form roller 4 is in contact with the plate on a plate cylinder and rotates and furnishes ink to the plate. Transfer roller 36 i which is positioned between the fountain roller 31 and i S69OB/438/3.6.2 f f

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16 ink fo m roller 4 rotates in parallel to them and has its outer circumferential surface in contact with the fountain roller 31, ink form roller 4 in succession and inking roller i. The ink fountain roller 31 is the minute hollow body dispersing roller In Fig. 33 and Fig. 34, the transfer roller 36 is the minute hollow body dispersing roller 10, and in Fig.

and Fig. 36, both fountain roller 31 and transfer roller 36 are the minute hollow body dispersing rollers The embodiments in Fig. 37 through Fig. 44 are similar to those in Fig. 29 through Fig. 36, except in these embodiments an ink film thickness regulating blade 7 near or in contact with the side face downstream of the ink furnishing device in the direction of rotation of the fountain roller 31 is provided. Furthermore, a blade 2 which is near or in contact with the side face downstream of the contact position of the ink form roller 4 in the direction of rotation of the inking roller 1 is provided to erease printing marks. Figures 37, 38, 39, 40, 41, 42, 43, and 44 correspond to Figures 29, 30, 31, 32, 33, 34, 35, and 36.

In Fig. 29 through Fig. 44, the peripheral speed of *the fountain roller 31 is set lower than the peripheral speed of the inking roller 1 with which the fountain roller 1 contacts and which is positioned downstream of the fountain roller 31 or transfer roller 36. The drive "means (not shown) of the fountain roller 31 is either the drive gear system for the ink furnishing device or specialising single drive means. In Figures 35, 36, 43, :and 44, the ink receiving layers 11 for both fountain roller 31 and transfer roller 36 need not be the same, namely the ratios of mixing of the dispersed minute hollow bodies need not be the same nor do the sizes of the minute hollow bodies 12 on them need to be the same.

Regarding the ratios of mixing of the hard material powder 14 in the ink receiving layer 11, it is not A, required that they are the same.

ST 9B/43813.6.92 7-E.

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17 In the foregoing description, only examples of cases in which the ink furnishing device is an ink reservoir 32 or an ink discharge body 33 were given, but other embodiments are also envisaged.

The above mentioned embodiments of the present invention related to an offset rotary printing machine, but they can be used with rotating letterpress machines which include flexographic printing machines.

In the embodiments described above, at first the ink is furnished to the fountain roller 31 so as to attach the ink to the outer circumferential surface of the roller 31 by means of an ink furnishing device.

When the ink furnishing device 6 is an ink reservoir 32, part of the fountain roller 31 is immersed in the ink in the ink reservoir to furnish ink to the outer circumferential surface of the fountain roller 31. When the ink furnishing device is an ink discharge body 33, the ink is discharged towards the outer circumferential surface of the fountain roller 31 from the ink discharge body 33 to furnish ink to the outer circumferential surface of the fountain roller 31.

When the fountain roller is a roller 1 which has minute hollow bodies dispersed on its outer circumferential surface part of the ink furnished to the fountain roller 31 is taken in the minute hollow bodies 12 which are dispersed and mixed on the outer circumferential surface of the inking roller 31 with the hollow sections of the minute hollow bodies 12 opened.

Then, as the fountain roller 31 rotates, the ink furnished to the outer circumferential surface of the i fountain roller 31 goes to the contact section between the ink fountain roller 31 and inking roller 1 or to the :contact section between the ink fountain roller 31 and transfer roller 36, and when the ink passes through either one of those contact sections, the ink is transferred to either the inking roller 1 or transfer roller 36.

iPI The peripheral speed of rotation of the fountain

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"-2690BI438/3.6.92 18 roller 31 is set slower than that of the inking roller and that of the transfer roller 36 so that the ink conveyed from the inking roller 1 or transfer roller 36 can be controlled. The ink which is at the contact section of the fountain roller 31 and inking roller 1 or at the contact section of the fountain roller 31 and transfer roller 36 and which is in excess is squeezed out from those contact sections and the excess ink stays on the upstream side of those contact sections with respect to the direction of rotation.

When the fountain roller 31 is a roller which has minute hollow bodies 12 dispersed on its outer circumferential surface, the ink which is received in the open minute hollow bodies in the ink receiving layer 11 is not squeezed out by the contact section of the rollers but is capable of passing through it. By increasing or reducing the amount of ink that is received in the minute hollow bodies 12 which are open, that is by changing the size of the minute hollow body 12 or changing the ratio of mixing of the hollow bodies to change the amount of ink that is received in the minute hollow bodies 12 that are open on the outer circumferential surface of the roller, it is possible to change the amount of the ink passing through the contact section, that is to change the amount of the ink transferred from the fountain roller 31 to the inking roller 1 or to the transfer roller 36.

•If the transfer roller 36 is a roller 1 which has the minute hollow bodies 12 on the outer circumferential surface of the roller, it is possible to increase or reduce and adjust the amount of the ink transferred from the above mentioned fountain roller 31 to the transfer roller 36. In other words, the amount of the ink received from the fountain roller 31 can be increased or reduced by changing the size of the minute hollow body in the ink receiving layer 11 that is provided on the PI-'k surface of the transfer roller 36 or changing the ratio Sof mixing of the minute hollow bodies 12 to increase or 0' S:20690B/438/3.8.92 19 reduce the amount of ink received in the minute hollow bodies 12.

The ink that is transferred to the transfer roller 36 reaches the contact section of the transfer roller 36 and inking roller 1 as the transfer roller rotates, and when the ink passes through the contact section, the ink is transferred to the inking roller 1.

The ink that is transferred from the fountain roller 31 or transfer roller 36 to the inking roller 1 reaches the contact section between the inking roller 1 and the ink form roller 4 as the inking roller 1 rotates, and when the ink passes through the contact section, the ink I is transferred to the ink form roller 4 and the ink on this roller is in turn furnished to the plate on the plate cylinder P.

On the other hand, an ink film thickness regulating blade 7 and previous print mark erasing blade 21 as shown in Fig. 37 through Fig. 44 act respectively as follows.

The ink film thickness regulating blade 7 is installed for the fountain roller 31 and regulates beforehand the amount of the ink that reaches the contact section between the fountain roller 31 and intermediate roller or the contact section between the fountain roller 31 and transfer roller 36 as the fountain roller 31 25 rotates. The blade 7 contributes to preventing ~unexpected mishaps such as the total amount of ink passed to the fountain roller 31 being squeezed at the above mentioned contact section as the fountain roller 31 rotates and staying in a large amount at the contact section on the upstream side. Part of this ink passes through the above mentioned contact section by widening it forcibly as the inking roller 1 or transfer roller 36 rotates. When the fountain roller 31 is a roller 1 which has minute hollow bodies dispersed on its outer circumferential surface, it is possible by bringing the ink film thickness regulating blade 7 in contact with the 4. 'ountain roller 31 to regulate the amount of ink that reaches the above mentioned contact section as the

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S:20690B1438/3.8.92 fountain roller 31 rotates to an amount which is almost equal to the amount of ink that is received in the minute hollow bodies 12 that are open on the outer circumferential surface of the roller. This is very effective in easily regulating the amount of ink passing through the above mentioned contact section.

The previous print mark erasing blade 21 is for uniformly spreading or removing ink on the outer circumferential surface of the inking roller 1 which is transferred to it from the ink form roller 4. The uneven distribution of ink that is left on the ink form roller 4 after furnishing ink to a plate is eliminated by the blade 21 on the inking roller to which the uneven ink distribution is transferred, eliminating at the same time the uneven furnishing of ink to the images and lines on a plate by continuing the above mentioned state of the uneven ink distribution on the roller and preventing thereby thick and thin tones on the print, so called 'ghost'. Further, according to the present invention, the peripheral speeds of rotation of the fountain roller 31 and inking roller 1 or those of the fountain roller 31 and transfer roller 36 are different so that there is friction at the contact section of those rollers, causing wear on one of those rollers. But when a roller which 25 has minute hollow bodies dispersed on its circumferential surface is used for at least one of the fountain roller 31 and inking roller 1 or the fountain roller 31 and io ":transfer roller 36, there will be no significant unfavorable change on the outer circumferential surface of the roller until the ink receiving layer 11 on it is worn out. This is because there are minute hollow bodies 12 in the ink receiving layer 11 and the minute hollow bodies 12 that are dispersed and mixed in the ink receiving layer 11 and are successively exposed on the 35 outer circumferential surface as the ink receiving layer 11 is worn to open the shells of the minute hollow bodies. By providing a hard material powder 13 dispersed and mixed with the minute hollow bodies on the

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S:20690B/438/3.6.92 21 ink rbceiving layer 11, the above mentioned wear is exclusively carried by the hard material powder 13 so that the wear in the ink receiving layer 11 is suppressed and the life of the roller is extended.

Since a roller which is provided with dispersed minute hollow bodies is subject to no significant change on its outer circumferential surface and it can be used for a long time even if its outer circumferential surface is worn, the frequency of replacing rollers becomes very small with the machine availability factor improved a good deal, The present invention is not limited by the embodiments in the above description and it should be understood that a modification is included as far as it does not go beyond the spirit of the invention as claimed in the claim.

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Claims

1. An ink furnishing device for printing machines which comprises a plurality of rollers arranged to form an ink furnishing route interconnecting an ink replenishing means with the surface of a plate, whereby contacting rollers of the furnishing route transfer ink from the replenishing means to the surface of the plate, wherein at least one of the rollers comprises an ink receiving layer having minute hollow bodies substantially uniformly dispersed throughout and arranged to be open at the outer peripheral surface of the at least one roller.

2. An ink furnishing device as claimed in claim 1 wherein the at least one roller comprises powder of a hard material uniformly dispersed throughout the ink receiving layer.

3. An ink furnishing device as claimed in claim 1 or 2 comprising an ink removal device for removing excess ink from the outer peripheral surface of the ink receiving layer.

4. An ink furnishing device as claimed in claim 3 wherein the ink removal device comprises a blade contacting the outer peripheral surface of the ink receiving layer.

5. An ink furnishing device as claimed in any one 25 of the preceding claims wherein the rollers comprise an ink furnishing device, inking roller and fountain roller.

6. An ink furnishing device as claimed in claim 3 wherein the ink removal device comprises a roller or bar in contact with the outer peripheral surface of the ink receiving layer.

7. An ink furnishing device according to any one of claims 1 to 4 wherein the rollers comprise an inking roller which is provided with the ink receiving layer.

8. An ink furnishing device according to any one of 35 claims 1 to 4 wherein the rollers comprise a fountain oo "V0: '"94l i roller which is provided with the ink receiving layer. LS:28 9 S-206908/438/3.6 .92 23

9. An ink furnishing device according to any one of the preceding claims wherein the minute hollow bodies have a diameter of between 5 and 300m. An ink furnishing device as claimed in claim 1 and substantially as hereinbefore described with reference to Figures 1 to 3 in combination with any one of Figures 5 to 44. Dated this 3rd day of June 1992 KABUSHIKIGAISHA TOKYO KIKAI SEISAKUSHO By their Patent Attorneys GRIFFITH HACK CO :o j *j L~y4